title: β2-adrenergic receptor genotype and other variables that contribute to labor pain and progress.
abstract: BACKGROUND
  β2-Adrenergic receptor (β2AR) activity influences labor. Its genotype affects the incidence of preterm delivery. We determined the effect of β2AR genotype on term labor progress and maternal pain.
  
  
  METHODS
  We prospectively enrolled 150 nulliparous parturients in the third trimester and obtained sensory thresholds, demographic information, and DNA. Cervical dilation, pain scores, and labor management data were extracted with associated times. The association of genetic and demographic factors with labor was tested using mixed effects models.
  
  
  RESULTS
  Parturients who express Gln at the 27 position of the β2AR had slower labor (P < 0.03). They progressed from 1-10 cm dilation in approximately 21 h compared with 14 h among other patients. Asian ethnicity, previously associated with slower labor, is highly associated with this polymorphism (P < 0.0001). Heavier and black patients had slower latent labor (P < 0.01, 0.01). Neuraxial analgesia was associated with slower labor progress (P < 0.0001). It could take up to 36 h for parturients who were black and/or more than median weight (165 lb) to transition from 1 cm cervical dilation to active labor. However, after this active phase began, labor rates among these patients were similar to that of other parturients.
  
  
  CONCLUSIONS
  We detected a strong association between β2AR genotype and slower labor. Asian ethnicity may be a proxy for β2AR genotype. Black women and those of higher than average weight have slower latent labor. These results confirm many of the associations found when this mathematical model was applied to a large retrospective cohort, further validating this approach to description and analysis of labor progress.
authors.affiliation: Division of Obstetrical Anesthesiology, Columbia University, New York, New York, USA. eli9003@nyp.org
authors.forename: Elena
authors.initials: E
authors.lastname: Reitman
authors.forename: Jessamyn
authors.initials: J
authors.lastname: Conell-Price
authors.forename: Jennifer
authors.initials: J
authors.lastname: Evansmith
authors.forename: Luke
authors.initials: L
authors.lastname: Olson
authors.forename: Sofia
authors.initials: S
authors.lastname: Drosinos
authors.forename: Nancy
authors.initials: N
authors.lastname: Jasper
authors.forename: Paula
authors.initials: P
authors.lastname: Randolph
authors.forename: Richard M
authors.initials: RM
authors.lastname: Smiley
authors.forename: Steven
authors.initials: S
authors.lastname: Shafer
authors.forename: Pamela
authors.initials: P
authors.lastname: Flood
mesh_terms: D000328:Adult; D044466:Asian People / Q000235:genetics / Q000706:statistics & numerical data; D044383:Black People / Q000706:statistics & numerical data; D005260:Female; D005838:Genotype; D006801:Humans; D048949:Labor Pain / Q000235:genetics*; D007743:Labor, Obstetric / Q000208:ethnology / Q000235:genetics*; D008954:Models, Biological; D050177:Overweight / Q000208:ethnology; D011110:Polymorphism, Genetic; D011247:Pregnancy; D011446:Prospective Studies; D018343:Receptors, Adrenergic, beta-2 / Q000235:genetics*; D013997:Time Factors
chemical_list: D018343:Receptors, Adrenergic, beta-2